It is well known that parts of the human body is subject to change in size according to the weather. That is the fingers swell in summer when subjected to heat and humidity such that rings that fit in the winter are tight fitting in the hot summer.
Just as fingers swell, so does the thumb. When a tournament bowler bowls over extended periods of time, the thumb can swell due to the influences of heat, perspiration, and even callouses. Since tournament bowlers be they amateur or professional have their own ball(s) which have been drilled to their finger and thumb dimensions, they are subject to discomfort should the thumb size change upwardly, i.e. become bigger in cross-section.
On the other hand, compensation by drilling the thumb hole wider in cross-section only causes problems during periods of standard dimension, i.e. the beginning of a tournament, cool weather etc.
While thumb inserts are known, for permanently reducing the diameter of the thumb hole, there has never been an adjustable thumb hole adapter which can be opened outwardly to enlarge the diameter of the thumb opening for adjustment during times of stress, i.e. thumb enlargement.
Typical of the prior art known by Applicant is U.S. Pat. No. 3,416,796 issue to Ginder. This patent discloses a cylindrical longitudinally-slotted finger-receiving insert which is axially movable within a cylindrical sleeve secured within the bowling ball's finger or thumb opening. A securing bolt that passes through a closure member at one end of the insert axially moves the tapered walls of the insert and sleeve to co-act to change the interior diameter of the insert without changing the angular relationship between the insert and the longitudinal axis. The device is quite complex in order to maintain a cylindrical balance within the finger or thumb opening as desired by the inventor thereof.
There is a need therefore for a simple thumb or finger receiving insert for a bowling ball which can be enlarged at will for use in bowling balls.
It is an object therefore of this invention to provide a device which can be mounted within a predrilled thumb bore of a bowling ball and which is manually adjustable to alter the diameter of the thumb opening.
It is another object to provide a device to narrow the thumb or finger opening in a bowling ball from the surface of the ball.
It is another object to provide a device to narrow the thumb opening in a bowling ball from within the thumb hole cylinder.
It is yet another object to provide a thumb hole insert that is within the guide lines of the American bowling Congress both as to weight and materials.
Other objects of the invention will in part be obvious and will in part appear hereinafter.
The invention accordingly comprises the apparatus possessing the construction, combination of elements and the arrangement of parts which are exemplified in the following detailed disclosure, and the scope of which will be indicated in the claims.